Posts

Just a few days ago we wrote about a slick more than 16 miles long on a Landsat-8 satellite image of the Taylor Energy chronic leak site in the Gulf of Mexico. We’ve also pointed out, many times, that the official spill reports that Taylor Energy is required to submit to the National Response Center typically describe a much smaller slick than what we have repeatedly observed on satellite images and from independent aerial overflights. Well, guess what? The latest weekly dump of NRC reports was just made available by the Coast Guard, and our faithful little report-scraping robot just pushed them out through our SkyTruth Alerts incident mapping and email-alerting system. And once again, what Taylor reported on May 7th doesn’t jive with what we observed in the Gulf that same day. Taylor reported a slick 9.7 miles long and half a mile wide, covering a total area of 4.85 square miles (12.56 sq km), based on an aerial overflight that took place at 9:15am local time on May 7. They estimate the total volume of oil in this slick amounts to 14.6 gallons.

We observed a slick more than 16 miles long and covering a total area of 5.95 square miles (15.4 sq km) on a Landsat-8 satellite image that was taken just two hours after Taylor’s overflight, at 11:25am. Based on a conservative thickness estimate of 1 micron for the slick, we calculate the slick holds 4,066 gallons of oil. Satellite image analysts with the federal government, at NOAA’s National Environmental Satellite, Data and Information Services division (NESDIS), have also been using satellite images to monitor the Gulf. They reported to the NRC a slick over 17 miles long, but didn’t give an area or volume estimate. Based on their description of the slick, we’re certain they were looking at the same Landsat-8 image that we analyzed. Our measurements of the slick length are comparable. So, SkyTruth and government analysts documented a slick almost twice as long as the slick Taylor reported. And our conservatively estimated volume is 278 times greater than Taylor’s report. Even if we take Taylor’s slick-length report at face value, applying a 1 micron thickness value to a slick covering 4.85 square miles yields a volume estimate of 3,316 gallons. To take that down to their total reported volume of only 14.6 gallons, you’d have to assume the oil only covered 0.4% of the 4.85 square mile area they reported as being an oil slick observable from the air. Seems unrealistic, doesn’t it?

The Associated Press recently ran an in-depth article and video on the chronic Taylor Energy oil leak in the Gulf, just a few miles of the top of the Mississippi Delta. We’ve heard the company claims they plugged all of the leaking wells on the seafloor at the site of their Hurricane Ivan-destroyed oil platform in 2011, and that any leaking oil since then is just “residual” oil oozing out of sediment on the seafloor. If that’s the case, it seems reasonable to expect the slick at that location to gradually get smaller, and ultimately disappear. But that’s not what we’re seeing on satellite imagery, and that’s not what is being reported on a near-daily basis to the Coast Guard’s National Response Center. This Landsat-8 satellite image taken yesterday (May 7, 2015) shows a slick emanating from the site and stretching to the west for at least 16 miles. Most of the slick appears dark in the image, indicating a thin sheen of oil; but for many miles it’s bounded along its northern edge by a distinct bright line that suggests much thicker, emulsified oil, like the “mousse” observed and sampled by Florida State University researchers last summer. Which makes us ask: have all of the wells actually been plugged, or was the work stopped before the job was completed?

How much oil is in this slick? It covers an area of 15.4 square kilometers. Assuming this slick was mostly a very thin “rainbow sheen” as has been repeatedly documented, a conservative estimate for the thickness is 1 micron (one-millionth of a meter). The bright line of thicker, emulsified oil is many times thicker than that. But to be conservative let’s assume that, on average, this slick is only 1 micron thick. That amounts to 264 gallons per square kilometer.

So yesterday, there was a slick holding at least 4,066 gallons of oil from the Taylor leak. Taylor has claimed the average daily leak rate is about 4 gallons. But thinly spread oil out in the Gulf can only survive for a matter of days before it’s broken down by evaporation, dissolution, dispersion, photolysis and biodegradation.

And that’s a ridiculous state of affairs in the 21st century. Almost 5 years after the BP spill riveted everyone’s attention on the risks of offshore oil production in the Gulf of Mexico and beyond, we’re still relying almost entirely on pollution reports submitted to the government by the polluters themselves who are, of course, subject to fines and other sanctions for those spills. Evidence of non-reporting and chronic under-reporting of oil spills was uncovered by our 2012 analysis of NRC reports and comparison with satellite imagery, an analysis recently validated in a peer-reviewed study published by scientists at Florida State University.

Some information is better than none, but the unverified and demonstrably inaccurate information we get is not a credible foundation for building public policy governing offshore oil and gas development.

This is the week that everyone will be rolling out their “5 Years After the BP Spill” stories. Scientists are pointing out how much we still don’t understand about the spill and its long-term impacts; environmental groups are warning that little has changed and we’re just as close to disaster now as we were on April 19, 2010; the federal government is announcing new rules to assure us that new drilling off the Atlantic coast and in the Arctic Ocean will be safe; industry is touting new containment technology to respond on the seafloor to any future loss of well control.

Some good news, some warnings that we’ve got a ways to go before we can relax when it comes to deepwater, high-pressure offshore drilling. One of our concerns is that despite the new containment technology — which is designed to stop a runaway well if we have another scenario very similar to BP’s infamous Macondo well — we’re still inept when it comes to cleaning up oil once it hits the water. The government’s estimate is we only managed to recover, burn, chemically disperse or divert 25% of the oil that gushed from Macondo.

Why does this matter?

Because we can’t confidently predict what will cause the next catastrophic oil spill. We’re always surprised when it happens. Maybe it will be the sinking of a fully loaded FPSO. Maybe it will be a seafloor landslide, like the one that hit the Taylor Energy platform, that wipes out a deepwater production hub connected to dozens of high-pressure wells. The abandonment of a deepwater well last week by Cobalt Energy is an example. In this case, they detected the failure of a seal on the riser pipe, and abandoned drilling before the well hit the reservoir target. Call that a successful failure, if you will. But if the well had already been in production, what would the worst-case scenario spill look like if there had been a total loss of well control?

Here is the worst-case discharge (WCD) summary from Cobalt’s federally approved oil spill response plan for their North Platte prospect. Note that “mbo” = thousands of barrels of oil.

The top-kill operation presumably envisions using one of the new well-containment “capping stack” devices. In that scenario, where the well doesn’t naturally bridge over by clogging itself with debris, it could take 30 days to successfully kill the well, resulting in a worst-case spill of 605,000 barrels of oil. That’s 25.4 million gallons of oil in the water. If we’re going to continue to push into deeper water, farther offshore, with wells tapping high-pressure reservoirs miles below the seafloor, maybe we should put a lot more effort into figuring out how to effectively clean up spilled oil.

If we can’t — or just plain won’t — do that, then we shouldn’t be drilling where the consequences of failure are high.

https://skytruth.org/wp-content/uploads/2015/04/Cobalt-worst-case-scenario-table.jpg4481086John Amos/wp-content/uploads/2016/08/test_logo.pngJohn Amos2015-04-13 14:47:002019-02-06 10:57:24Offshore Drilling: 5 Years After BP, How Bad Can A Spill Be?

And here is another interesting map, showing the cumulative oil slick “footprint” of BP’s 2010 spill in the Gulf of Mexico, superimposed on the Atlantic coast, assuming an out-of-control well located more than 50 miles offshore:

And here’s yet another map, showing the tracks of hurricanes along the Eastern seaboard from 2000 to 2013:

Tracks of hurricanes in the western Atlantic Ocean from 2000 to 2013. Source: NOAA.

In case you’ve missed our many posts on this topic, there is a continuous leak of oil in the Gulf of Mexico from the site of an oil platform that was knocked down by Hurricane Ivan more than 10 years ago. We’ve observed the slick at this location dozens of times since we “discovered” it in 2010, it’s been documented on overflights by the Gulf Monitoring Consortium and others, and it’s been sampled by scientists from Florida State University. Our most recent observation of the leak at that site last month showed a slick about 13 miles long. At times the slick has been more than 20 miles long (big enough to span the Beltway, for you DC-area readers). Cumulatively, we now estimate this leak has spilled anywhere from 300,000 gallons to nearly 1.4 million gallons of oil.

Not a very comforting prospect for those who live along the coast where new offshore drilling is being contemplated. By the way, you are encouraged to let the feds know what you think about this plan. Go here to submit your comments. The public comment period closes on March 30.

SkyTruth and/or its third party tools use cookies to monitor traffic in the aggregate on our websites and applications and to improve user experience. If you continue browsing, we'll assume you agree to the use of cookies. You can change your cookie settings at any time in your browser settings. Find out more in our privacy policy.